In the manufacturing of the optical fibers, the optical preforms are heated to temperatures much above the glass softening point and then drawn at large draw down ratios to form optical fibers 125 μm in diameter. Due to the high draw temperatures, large draw down ratios and fast draw speeds, the glass is far from the equilibrium state, resulting in fibers with high fictive temperature. High fictive temperature is undesirable for fibers used for transmission of optical signals because high fictive temperature is known to correlate with increased signal attenuation. To reduce signal attenuation in transmission fibers, it is desirable to modify fiber processing conditions to produce fibers with lower fictive temperature. Efforts to reduce fictive temperature have emphasized slow cooling of the fiber to stabilize the fiber in a state closer to the equilibrium state. Prolonged cooling of the fiber in a critical temperature regime in the glass transition region of the fiber is one strategy for reducing fiber fictive temperature. The extent to which fiber fictive temperature can be reduced in existing fiber processing systems, however, is limited because the residence time of the fiber at temperature within the critical regime are too short (<0.2 sec) to permit significant relaxation of the structure of the glass. Because of the short residence time, the structure of the glass remains far from the equilibrium state and only a modest decrease in fictive temperature is achieved. It would be desirable to develop methods of fiber processing that enable the production of fibers having low fictive temperature.